Authorities continue to investigate lingering questions

Below:

The young federal prosecutor had come so far to end up sprawled face down in a creek in rural Lancaster, Pa., drowned, with 36 shallow stab wounds on his clothed body. The death of Jonathan Luna, 38 years old, husband, devoted father of two small children was and is a perplexing mystery, a hard-working lawyer mourned by his colleagues at the U.S. Attorney's Office in Baltimore.

"He served this office,” says U.S. attorney Thomas DiBiaggio. “He served the community and the interest of justice with great dedication and commitment."

As an assistant U.S. attorney in Baltimore he'd put away dozens of bad guys, drug dealers, sexual predators and before that in Brooklyn, New York as a young assistant district attorney. It wasn't hard to imagine someone from the prosecutor's professional past getting even. Or was it something else entirely that could explain how this young man from some of the tougher streets of New York wound up dead in the middle of the night in a creek in Amish country?

The long line of those who speak well of Jonathan Luna forms behind his close friend and onetime law school roommate at the University of North Carolina, Reggie Shuford.

"The brutality of his murder is directly opposite to the gentle way that he lived his life,” says Shuford. “He was an easy-going person. Anyone could get along with Jonathan… charming, gregarious, gentle, you name it. You know, if you got out a thesaurus and looked up all the good things, his name would be there."

Luna grew up in New York--the South Bronx, a rough and tumble neighborhood he was never ashamed of but he'd decided early on he wanted to break away from. education and determination were his ticket out, with Fordham University, then Law School at U.N.C.

And when he graduated and passed the bar, no one was surprised when his idealism took him to the Brooklyn district attorney's office. By then he was married to a doctor.

"He was very very proud of his wife who was an accomplished professional person in her own right,” says Shuford.

In 1999 Luna applied for a position as an assistant U.S. Attorney in Baltimore. Judge Lynne Battaglia was then Maryland's U.S. Attorney. She interviewed Jonathan.

"I remember him walking in the door,” says Battaglia. “He had a bowtie on. and he was very energetic from the beginning. Came in, shook hands and basically commanded the room.”

He beat out thousands of other candidates.

"I think Jonathan was more concerned about making a difference than he was about becoming a rising star, says Battaglia. “He believed that by making communities safer, he could make a difference."

It's no trouble finding people who speak well of Jonathan Luna. The difficulty is finding the person or persons who stabbed him and left him for dead. What happened during the last hours of Jonathan Luna's life?

Unexplained journey

On the evening of December 3, he was in the federal courthouse wrapping up the final details of his successful prosecution of two men accused of drug dealing. He'd been working by phone and fax with the one of the defendant's lawyers on the terms of the plea agreement which would be presented to the Judge the following morning.

Luna reportedly went home that night, but then returned to the office to finish his work. At 11:30 p.m., when he left the courthouse, he was under no apparent duress.

His final journey is a story told mostly by credit card transactions. In his silver Honda Accord he drove north out of Baltimore up Interstate-95 and exited in Delaware where he withdrew $200 from an ATM machine. He continued on north but did something curious. Instead of paying a toll with his EZ-pass gizmo as he'd done so far that night, he went through the cash lane at a tollbooth.

Sometime after 2 a.m. he bought gas at a Sunoco station in King of Prussia, Pa., one ofPhiladelphia's busy western suburbs.

At 5:30 a.m. on a country road just off the highway in rural Lancaster county -- roughly 70 miles from Luna's home near Baltimore -- a man working on the property saw a red light in the distance and went over to check it out. He told his co-workers what he discovered.

“He realized it was a car,” says the co-worker. “And when he seen the blood on the outside of the door, he said, in his mind it was an injury accident so he called 911. And then the police came.”

The police discovered the body facedown in a creek just a few feet away from the still idling car, the victim wearing a business suit. Investigators took photos and made notes. Newspapers reported the grisly findings: Three dozen stab wounds about the neck and chest made with something like a penknife; bruising in the groin area; a head wound; blood in the back seat of the car; the victim's ID and cash still on him.

Back in Baltimore later that morning, few were aware yet that Luna was even missing. Federal court convened at 9:30 a.m. in the case of the two drug dealers -- and there's no prosecutor. Gail Gibson, a reporter for the Baltimore Sun, had been covering the thus far routine case.

“As the morning went on, you know, there was a real sense of dread in the courtroom, because I don't think anybody sitting in there felt like this was going to end well,” says Gibson.

In New York, Luna's friend Reggie heard the first headlines only that Jonathan was missing.

“Within a matter of seconds, I called his home and spoke with his mother-in-law who told me that the authorities were there, and that they had just provided the news that they had found his body that morning. It's very difficult.”

Targeting a federal prosecutor is rare statistically, still after the shock came the inevitable fear that was Jonathan's death was work related. Had someone he once prosecuted come back for revenge? Luna's death reminded his former boss, Judge Battaglia, of just how dangerous the job can be.

“Jonathan's murder brought all that back,” says Battaglia. “Thinking about how wonderful it is to be able to give people jobs like that. But also, what a burden it can be for their families and them, should something happen.”

“The most natural place to look was at Jonathan's case load and at the defendants in the case he was prosecuting that week,” says Gibson. “There was no way around it. It was the most obvious thing to look at.”

Search for clues

FBI agents descended on the courthouse and authorities vowed to find the killer. But finding someone to bring to justice is proving to be as twisted and baffling as the path Jonathan Luna followed on that last night of his life. There were puzzling circumstances. Why did Luna drive so far from home, so late at night, when he was due back in court at 9:30 the next morning? What was he doing in Delaware and Pennsylvania? Who would brutally attack a young man so universally beloved?

“Baltimore heroin dealers typically are not going to stab people and take them up to rural Pennsylvania,” says Gibson. “They're going to shoot somebody in the head and leave him in a row house on the east side of town. So even from the start the case didn't make sense as a drug hit.”

Authorities seemed to find no link between the case that Luna was prosecuting and his death, so the focus broadened to Luna's life outside of work.

Word leaked out that authorities reportedly found evidence of an Internet message soliciting sex from women, though the posting could not definitively be linked to Luna. Also, investigators had delved into Luna's financial affairs, and reportedly found hidden credit card debt. In the absence of hard information, the alleged secrets fueled buzz.

“One thing I think that's truly sad about this case is that what is coming out about Jonathan's life is left with the impression of it being completely true, and the person who would know best, Jonathan, isn't, you know, can't tell us, or explain to us or interpret for us the kinds of details that we're hearing at this point,” says Gibson.

Former FBI profiler Clint Van Zandt is used to dissecting crime scenes. In this case, he says the brutality of the attack shows the assailant was probably enraged.

“This is a true mystery,” says Van Zandt. “A knife is something up close and personal. That's something you're looking right into the face, right into the eye of the person you're killing.”

As forensic tests come back, the crime scene could yield more clues. Was there more than one person's blood in the car? Was Luna incapacitated in some way that made him unable to fight back? Authorities are carefully keeping the details of the investigation under wraps.

“The challenge to the authorities again, is going to be motive,” says Van Zandt. “Who would have the motive to do this to him? And how would these stars, how would these planets link up? How would this person, Jonathan Luna, in the middle of the night have the unfortunate or planned contact with one or more other people who would eventually take his life?”

Jonathan's murder is unsolved. That hasn't stopped speculation about possible causes. That leaves friends and family, playing “Clue,” almost, with regard to what happened to Jonathan Luna.

“It's painful to the extent that it all too quickly became speculative, and personal, and salacious,” says Shuford. “It is not painful, to the extent that most of us have avoided that coverage, and also because we know what a great person Jonathan was. And we know his character. And nothing can shake that.”

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.